上海市8所医院供水系统军团菌属污染调查及危险因素分析

Contamination of Legionella spp.in Water Distribution Systems in 8 Hospitals of Shanghai,China

目的了解上海市医院供水系统管道中军团菌属的污染情况,并分析军团菌属污染的危险因素。方法在2009年5-9月采集上海市8所医院供水管道末端水样共193份,分别进行军团菌和阿米巴的培养,应用军团菌乳胶凝集试验将所分离的军团菌属进行血清分型,同时收集相关资料进行危险因素分析。结果在采样的8所医院中,7所(87.5%)医院有军团菌属的污染,2所医院水管出口嗜肺军团菌污染率>30.0%;在采集的193份水样中,83份(43.0%)分离出军团菌属,其中33份(17.1%)分离到嗜肺军团菌,63份水样中军团菌属的浓度≥103CFU/L;在军团菌属污染危险因素分析中,阿米巴的定植、无水管消毒、水管类型为镀锌钢管及水箱间接供水都是独立的危险因素。结论上海市医院供水系统中军团菌属污染常见,且污染浓度高,存在发生医院内军团菌肺炎甚至暴发流行的严重隐患,建议对医院供水系统军团菌属污染情况和医院获得性军团菌病进行监测,并研究具有可行性的供水系统去除军团菌污染的有效方法 。

OBJECTIVE To investigate the contamination of legionella spp. in hospital water distribution systems, and analyse the associated risk factors. METHODS 193 water samples were collected from the distribution systems of 8 hospitals in Shanghai and the water samples were cultured for legionellaspp, and amoeba, latex agglutination test were used to identify the serogroups of legionella that have been isolated. Meanwhile, the associated factors of legion Ella contamination were collected. RESULTS Among the 8 sampling hospitals, 7 （87. 5%） were contaminated by legionella spp. 2 hospitals were detected with high level contamination （〉30%） of legionella pneumophila. In 193 water samples that have been collected, 83 （43. 0%） were positive for legionella spp, including 33 for legionella pneumophila. Among the positive samples, as many as 63 samples had the concentration ≥10^2 cfu/L. In the risk factors analysis for legion Ella contamination, the contamination of amoeba, lack of distribution system disinfection, use of galvanized steel pipe and use of tank for water distribution were independent risk factors. CONCLUSIONS Most of the investigated hospitals have high level contamination and high concentration of legionella spp. in Shanghai, which would likely to acquire legionellosis. Active surveillance of water distribution systems and nosocomial acquired legion Ella pneumonia should be conducted and disinfection of the water distribution system should be considered.